Currently used fertilizer utilization rate is low, mainly for nitrogen fertilizer, especially when urea is applied to soil, under the action of water and urease, the nitrogen is dissolved into amide state, the amide nitrogen fertilizer was further decomposed into NH4 and CO2, nitrification of NH4 is produced under the action of soil microorganisms, and part of it is transformed into NO2—, NO2, the other part of it is transformed into HNO3 and nitrates, NO2-nitrosamine salt is carcinogenic substances, NO2 gas evaporates from the soil and destroys the ozone layer, excessive nitrate infiltration causes groundwater pollution and eutrophication of rivers and lakes. Urea yield in China is more than 60 percent of the yield of total fertilizer, during the industrialization of urea production, the country invested a lot of energy and money to produce fertilizer, however, due to the easy decomposition of urea into soil, the nitrogen utilization rate was only 35%, this means energy waste and inefficiency, at the same time, it also brings serious environmental pressure. In order to improve the utilization rate of fertilizer, the utility model uses nano-carbon sol as urea synergist to add into urea during the process of urea preparation to improve the utilization rate of fertilizer. The development of nano-carbon fertilizer can solve the problems of fertilizer utilization and environmental protection, it is of great significance to achieve zero growth of fertilizer application and green sustainable development of agriculture.